Typically, electronic devices include one or more image sensor modules for providing enhanced media functionality. For example, the typical electronic device may utilize the image sensor modules for photo capturing and video teleconferencing. Some electronic devices include additional image sensor devices used for other purposes, such as a proximity detector.
For example, the electronic device may use the proximity detector to provide object distances for providing focusing adjustment to the camera purposed image sensor modules. In mobile device applications, the proximity detector may be used to detect when the user's hand is nearby, thereby quickly and accurately waking the device from a power saving sleep mode. Typically, the proximity detector comprises a light source directing radiation to a potential nearby object, and an image sensor receiving the radiation reflected off of the nearby object.
For example, U.S. Patent Application No. 2009/0057544 to Brodie et al, assigned to the present application's assignee, discloses an image sensor module for a mobile device. The image sensor module comprises a lens, a housing carrying the lens, and a lens cap over the lens and housing. The image sensor module includes a barrel mechanism for adjusting the lens. During manufacture of an electronic device including one or more image sensor modules, there is a desire to manufacture the electronic device as quickly as possible, particularly in mass production runs.
The typical image sensor module is manufactured in a multi-step process. The first steps include semiconductor processing to provide the image sensor integrated circuit (IC). The next steps include some form of testing for the image sensor IC and packaging. The image sensor IC may be assembled into the image sensor module, along with a lens and movable barrel if needed. This assembly of the image sensor module may be performed manually or via machine. For example, in electronic devices that use surface mounted components, a pick-and-place (P&P) machine may assemble the components onto a printed circuit board (PCB). A drawback to such singular packaging is that it may be relatively inefficient and also may require that each device be tested individually, adding to the manufacturing time.
An approach to an image sensor is disclosed in U.S. Patent Application Publication No. 2012/0248625 to Coffy et al., assigned to the present application's assignee. This image sensor comprises a transparent support, a pair of ICs on the transparent support, and encapsulation material on the transparent support and surrounding the pair of ICs.
Referring now to FIG. 1, a proximity detector 20, as in the prior art, includes a dielectric layer 26, an image sensor IC 24 on the dielectric layer, a light source device 22 also on the dielectric layer, and an adhesive material 25 between the image sensor IC and the dielectric layer. The proximity detector 20 includes a cap 21 positioned on the dielectric layer 26 and having a plurality of openings 31, 32a-32b therein, and transparent adhesive material 23 covering the light source device 22. The proximity detector 20 also includes a lens 27 carried by the cap 21, and a plurality of wire bonds 29a-29c coupling the image sensor IC 24 and the light source device 22 to electrically conductive traces on the dielectric layer 26. The proximity detector 20 also includes additional transparent adhesive material 28 between the image sensor IC 24 and the lens 27. A potential drawback to this proximity detector 20 includes a multi-step high precision assembly process using a P&P device. Also, the proximity detector 20 may be less reliable and difficult to integrate into mobile devices, due to size constraints.